1. Field of the Invention:
This invention relates to an electrical connection structure between a liquid crystal panel equipped with a ferroelectric liquid crystal and an external control circuit.
2. Description of the Related Art:
In the art, the method is well known of connecting an FPC (flexible printed circuit) with a liquid crystal panel by thermocompression bonding of an anisotropic conductive film which is composed of an insulating resin containing dispersed conductor particles.
Recently, a ferroelectirc liquid crystal element with memory characteristics has been disclosed in U.S. Pat. No. 4,367,924 to Clark et al., etc. This ferroelectric liquid crystal element is applicable to a display panel utilizing the multiplexing drive proposed by Kanbe et al. in U.S. Pat. No. 4,655,561, etc., from which a high definition display on a wide liquid crystal screen is to be expected.
As clearly shown by Okada et al. in U.S. Pat. No. 4,639,089, etc., the above-mentioned liquid crystal element can only present a monodomain orientation when it is gradually cooled down (ca. 5 C/hr.) from an isotropic phase on the high temperature side until a chiral smectic phase is attained after going through a cholesteric phase and a smectic A phase. Under existing circumstances, a monodomain orientation is not to be obtained when the temperature is raised or lowered rapidly to attain a chiral smectic phase or an isotropic phase.
As will be understood, the above-mentioned conventional method of electrically connecting a liquid crystal panel with an external control circuit by thermocompression bonding involves a partially or entirely rapid heating of the liquid crystal element. Accordingly, when this method is applied to the above-mentioned ferroelectric liquid crystal element, the rapid heating and subsequent cooling of the element may prevent it from attaining a monodomain orientation when the chiral smectic phase is regained. Such a disturbance in the orientation may be changed to the monodomain state by a re-orientation process. This, however, involves some problems: for example, employment of an anisotropic conductive adhesive mainly composed of a conventional thermoplastic resin during re-orientation will increase the connection resistance, as will be described later.